Female electrical terminal having overstress members

ABSTRACT

The female terminal of the present invention is equipped with a bottom plate (11) which extends in the forward-rearward direction, side plates (12a, 12b) which rise vertically from both side edges of the bottom plates (11), two upper contact parts (14a, 14b) which are formed by bending the respective free ends of the side plates (12a, 12b) inward so that the free ends face the bottom plate (11), and a lower contact part (15) which extends rearward from the vicinity of the front end portion (11c) of the bottom plate (11) on the side where a mating tab terminal is inserted, and which has a projection (16) on its upper surface. A mating tab terminal is inserted so that a home in the tab terminal engages with the projection (16), the female terminal is further equipped with arm parts (20a, 20b) which rise vertically from both side edges of the bottom plate (11) and part of the side plates (12a, 12b), with the free ends (21a, 21b) of the arm parts being bent back over the upper contact parts (14a, 14b).

FIELD OF THE INVENTION

The present invention concerns a female terminal in which electricalcontact with a mating tab terminal is accomplished by inserting said tabterminal.

BACKGROUND OF THE INVENTION

Conventionally, female terminals such as the terminal disclosed in, forexample, Japanese Utility Model Application No. 1-132072 have beenwidely used as female terminals of this type.

FIG. 14 is a schematic diagram of the above mentioned conventionalfemale terminal.

As is shown in FIG. 14, this female terminal 10 is equipped with abottom plate 1, side plates 2a and 2b which rise vertically from bothside edges 1a and 1b of the bottom plate 1, two upper contact parts 4aand 4b which are formed by bending the respective free ends 3a and 3b ofthe side plates 2a and 2b inward so that these free ends face the bottomplate 1, and a lower contact part 5 which extends rearward from thevicinity of the front end portion 1c of the bottom plate 1 on the sidewhere a mating tab terminal 9 is inserted, and which has a projection 6formed on its upper surface. Furthermore, the rear end portion of thelower contact part 5 extends rearward and is bent upward so that apressing part 5a is formed, and a portion of the bottom plate 1 extendsrearward and forms a barrel 7 which is used for the connection of wires.When a mating tab terminal 9 which has a hole 9a formed in a positioncorresponding to the projection 6 of the lower contact part 5 isinserted between the upper contact parts 4a and 4b and lower contactpart 5 of the female terminal 10 constructed as described above, thehole 9a in the tab terminal 9 and the projection 6 on the femaleterminal 10 engage so that the female terminal 10 and tab terminal 9 areconnected. When the tab terminal 9 is to be removed from the femaleterminal 10, the engagement of the projection 6 and hole 9a is releasedby pressing the pressing part 5a downward so that the lower contact part5 is caused to bend downward with a point in the vicinity of the frontend portion 1c of the bottom plate 1 acting as a supporting point.

However, in the female terminal 10 described above, the upper contactparts 4a and 4b have a cantilever beam structure. As a result, thefollowing problem arises: i. e., if an unreasonable amount of force isapplied to the upper contact parts 4a and 4b as a result of the tabterminal 9 being inserted from an incorrect insertion direction when thetab terminal 9 is inserted between the upper contact parts 4a and 4b andthe lower contact part 5, the upper contact parts 4a and 4b are easilydeformed.

Furthermore, since the pressing part 5a in the female terminal 10described above is formed by extending the rear end portion of the lowercontact part 5 in the rearward direction, the overall female terminalmust have a length equal to the total of the length of the lower contactpart 5 and the length of the pressing part 5a. Accordingly, this createsa restriction in terms of reducing the overall size of the femaleterminal 10.

SUMMARY OF THE INVENTION

In light of the above facts, the object of the present invention is toprovide a compact female terminal which makes it possible to preventdeformation of the female terminal when a tab terminal is inserted.

The invention is directed to a female terminal having a base plate, sideportions extending upwardy from the base plate, upper contact partsformed at ends of the side plates, a lower contact part extendingrearwardly from a forward part of the base portion and having aprojection thereon for engaging a mating tab terminal with a hole forengagement with the projection. Arm parts extend upwardly from the baseplate and free ends of the arm parts are bent over the upper contactparts. The free ends are above the upper contact parts thereby providingoverstress protection to the upper contact parts.

The invention is further directed to a female terminal having a bottomplate, side plates which extend upwardly from the bottom plate, twoupper contact parts formed on ends of the side plates, a lower contactpart which extends rearwardly from a forward part of the bottom plateand having a projection thereon for engaging a mating tab terminal witha hole for engagement with the projection. A pressing part extends fromthe lower contact part. The pressing part has an L-shaped cut thatextends between an intermediate portion of one side edge of the lowercontact part and the rear end portion of the lower contact part is cutand raised upward with the rear end portion of the lower contact partacting as a supporting point, and releases the engagement between thelower contact part and the tab terminal by being pressed downward sothat the lower contact part is caused to bend downward with a point inthe vicinity of the front end portion of the bottom plate acting as asupporting point.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way ofexample with reference to the accompanying drawings, in which:

FIG. 1 is an isometric view of a first embodiment of the female terminalof the present invention.

FIG. 2 is a partial sectional view along line 2--2 in FIG. 1.

FIG. 3 is an enlargement illustrating the pressing part in the femaleterminal shown in FIGS. 1 and 2.

FIG. 4 shows the sheet metal punch-out pattern used in the manufactureof the female terminal of the first embodiment.

FIG. 5 is a partial detailed view of the projection portion shown inFIG. 4.

FIG. 6 shows a top view which illustrate a second embodiment of thefemale terminal of the present invention.

FIG. 7 shows a partial cross sectional view along line 7--7 in FIG. 6.

FIG. 8 shows a side view of the female terminal of FIG. 6.

FIG. 9 shows a front view of the female terminal of FIG. 6.

FIG. 10 shows a partial top view which illustrates a third embodiment ofthe female terminal of the present invention.

FIG. 11 shows a partial cross sectional view taken along line 11--11 inFIG. 10.

FIG. 12 shows a cross-sectional view of the female terminal of FIG. 10taken along line 12--12 thereof.

FIG. 13 shows an enlargement of the pressing part of the female terminalshown in FIG. 10.

FIG. 14 is an isometric view of a prior art female terminal.

FIG. 1 is a schematic diagram which illustrates a first embodiment ofthe female terminal of the present invention. FIG. 2 is a partialsectional view along line 2--2 in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

As is shown in FIGS. 1 and 2, this female terminal 100 is equipped witha bottom plate 11 which extends in the forward-rearward direction, sideplates 12a and 12b which rise vertically from both side edges 11a and11b of the bottom plate 11, two upper contact parts 14a and 14b whichare formed by bending the respective free ends of the side plates 12aand 12b inward so that these free ends face the bottom plate 11, and alower contact part 15 which extends rearward from the vicinity of thefront end portion 11c of the bottom plate 11 on the side where a matingtab terminal is inserted, and which has a projection 16 formed on itsupper surface. Beads 14c and 14d which protrude downward arerespectively formed on the upper contact parts 14a and 14b, and themating tab terminal which is inserted between the upper contact parts14a and 14b and lower contact part 15 of the female terminal 100 makeselectrical contact with these beads 14c and 14d and the lower contactpart 15. A hole or recess is formed in the mating tab terminal in aposition corresponding to the projection 16 of the lower contact part15, and this hole or recess engages with the projection 16 so that thefemale terminal 100 and mating tab terminal are connected. Furthermore,a portion of the bottom plate 11 extends rearward and forms conductorbarrels 17a and 17b which are used for the connection of wires 18a, andinsulation barrels 17c and 17d which are used to fasten the insulatingmaterial 18b of the wires in place.

Furthermore, the female terminal 100 is equipped with arm parts 20a and20b which rise vertically from both side edges 11a and 11b of the bottomplate 11 and separate from the side plates 12a and 12b. The free ends21a and 21b of the arm parts 20a and 20b are bent back over the uppercontact parts 14a and 14b in positions 22a and 22b which are locatedabove the upper contact parts 14a and 14b and which are separated fromthe upper contact parts 14a and 14b. Furthermore, protruding portions23a and 23b which are caused to protrude forward are formed in portionsof the free ends 21a and 21b by pressing portions of the free ends 21aand 21b.

Since the female terminal 100 is constructed as described above, even ifan unreasonable force is applied to the upper contact parts 14a and 14bas a result of insertion of the mating tab terminal from an incorrectdirection when the tab terminal is inserted between the upper contactparts 14a and 14b and lower contact part 15, the free ends 21a and 21band protruding portions 23a and 23b of the arm parts 20a and 20b inhibitany deformation of the upper contact parts 14a and 14b, so thatdeformation of the upper contact parts 14a and 14b is prevented. Thisfunction of the arm parts 20a and 20b will be referred to below as an"anti-overstress function".

Furthermore, the rear end portion 15b of the lower contact part 15 ofthe female terminal 100 of this embodiment has a pressing part 15a whichis formed by a process in which a portion of the lower contact partsurrounded by an L-shaped cut 15d that extends between an intermediateportion of one side edge 15c of the lower contact part 15 and the rearend portion 15b of the lower contact part is cut and raised upward withthe rear end portion 15b of the lower contact part 15 being caused toact as a supporting point.

FIG. 3 is a partial enlargement of the pressing part 15a in the femaleterminal 100 shown in FIGS. 1 and 2. Furthermore, in order to illustratethe manner in which a portion of the lower contact part 15 is cut andraised upward with the rear end portion 15b being caused to act as asupporting point, FIG. 3 is shown as a perspective view from thedirection indicated by arrow B in FIG. 1.

When this pressing part 15a is pressed downward, the lower contact part15 is caused to bend downward with a point in the vicinity of the frontend portion 11c of the bottom plate 11 acting as a supporting point, sothat the engagement of the lower contact part 15 and the mating tabterminal is released.

Next, the method used to manufacture this female terminal 100 will bedescribed.

FIG. 4 is a diagram which illustrates the sheet metal punch-out patternused in the manufacture of the female terminal 100 of the firstembodiment.

As is shown in FIG. 4, a bottom plate portion 41, side plate portions42, upper contact part portions 44, projection portion 46, pressing partportion 45a, arm part portions 50, arm part free end portions 51,conductor barrel portions 47a and insulation barrel portions 47b whichare used to form the female terminal are punched out of a metal sheet ina single integrated shape.

The arm part portions 50 are separated from the side plate portions 42and upper contact part portions 44 by slits 51a formed at the tip endsof the arm part free end portions 51 and punched-out portions 48b and48c which connect with these slits 51a.

The lower contact part portion 45 and pressing part portion 45a areseparated from the bottom plate portion 41 by a punched-out portion 48d,a slit 45d and a punched-out portion 48e; furthermore, the pressing partportion 45a is formed into the shape shown in FIG. 3 by a process inwhich an L-shaped cut portion 45c formed by the punched-out portion 48dand a slit 45b is pulled upward with the broken line 45f shown in thevicinity of the punched-out portion 48f used as a supporting point.Moreover, bead portions 48a which protrude downward and form the actualcontact surfaces with the mating tab terminal are formed in the uppercontact part portions 44.

FIG. 5 is a partial detailed view of the projection portion shown inFIG. 4.

As is shown in FIG. 5, the projection portion 46 is formed, during thepunching of the metal sheet, into a shape which is such that a portionof the bottom plate 41 protrudes upward as an inclined surface rising tothe right along the direction in which the mating tab terminal isinserted, i. e., in the direction indicated by arrow A.

After the metal sheet has been punched out, as shown in FIGS. 4 and 5,the various parts are subjected to specified deformation working, thuscompleting a female terminal 100 of the shape shown in FIG. 1. Theportion of this deformation working that concerns the anti-overstressfunction mentioned above will be described below with reference to FIGS.1, 4 and 5.

The side plate portions 42 are bent inward from both side edges 11a and11b of the bottom plate portion 41, thus forming the side plates 12a and12b. The free ends of the side plates 12a and 12b are bent even furtherinward toward the bottom plate, thus forming the upper contact parts 14aand 14b. Furthermore, the arm part portions 50 are separated from theside plates 12a and 12b at both side edges 11a and 11b of the bottomplate portion 41, and the free ends 21a and 21b are bent back over theupper contact parts 14a and 14b in positions located above the uppercontact parts 14a and 14b, so that the resulting arm parts perform ananti-overstress function which prevents deformation of the upper contactparts 14a and 14b.

In order to insure that the free ends 21a and 21b of the arm parts 20aand 20b are bent back over the upper contact parts 14a and 14b, it isnecessary to form the upper contact parts 14a and 14b so that after thefree ends of the side plates 12a and 12b have been bent inward so thatthese free ends face the bottom plate, the upper contact parts 14a and14b are bent even further inward so that [i] the free ends 21a and 21bof the arm parts 20a and 20b reach the positions 22a and 22b locatedabove the upper contact parts 14a and 14b, and [ii] the respective partsoverlap sufficiently. Furthermore, the protruding portions 23a and 23bof the free ends 21a and 21b act to supplement the anti-overstressfunction by further widening the overlapping portions described above.

Next, a second embodiment of the female terminal of the presentinvention will be described.

FIGS. 6-9 show a second embodiment of the female terminal of the presentinvention. FIG. 6 is a plan view, FIG. 7 is a partial sectional viewalong line 7--7 in FIG. 6, FIG. 8 is a side view of FIG. 6, and FIG. 9is a side view of FIG. 7 from the tab terminal insertion side, (i. e.,from the direction indicated by arrow C).

FIGS. 6 through 9 show a female terminal 60 which is equipped with abottom plate 61, side plates 62a and 62b, upper contact parts 64a and64b, a lower contact part 65, a projection 66, a pressing part 65a, armparts 70a and 70b, arm part free ends 71a and 71b, conductor barrels 77aand 77b, insulation barrels 77c and 77d and the like. Furthermore, thebroken line 69 indicates the insertion position of the mating tabterminal.

In the female terminal 60 of the second embodiment the presentinvention, the free ends 71a and 71b of the arm parts are bent back overthe upper contact parts 64a and 64b in positions located above the uppercontact parts 64a and 64b, so that the free ends 71a and 71b of the armparts perform an anti-overstress function with respect to the uppercontact parts 64a and 64b.

In the female terminal 60 of the second embodiment, the pressing part65a, which is formed on the rear end portion of the lower contact part65, is cut and raised in the direction indicated by arrow D with a firstbent portion 65d being caused to act as a supporting point, and is thencut and raised in the direction indicated by arrow E with a second bentportion 65c being caused to act as a supporting point, so that the crosssection of the pressing part 65a is formed into a right-angled shape. Bythus cutting and raising the pressing part 65a in two stages, it ispossible to increase the height H of the pressing part 65a whilecurtailing the overall length of the lower contact part 65.

Furthermore, in the female terminal of the second embodiment, projectingparts 65d are formed on the rear end portion of the lower contact part65 by making the shape of the lower contact part portion that is punchedout of the bottom plate portion, when the female terminal is punched outof a metal sheet, a T shape as indicated by the outline 61e shown inFIG. 6. As a result of the rear end portion of the lower contact part 65in the vicinity of these projecting parts 65d being cut and raised inthe direction indicated by arrow E in FIG. 7, the horizontal positionsof the projecting parts 65d are shifted to the left so that theprojecting parts 65d and the edges 61f of the bottom plate 61 overlapabove and below (with a space left in between). Accordingly, even if anunreasonable force is applied to the lower contact part 65 as a resultof the tab terminal being inserted from an incorrect insertiondirection, the projecting parts 65d contact the edges 61f of the bottomplate 61 so that an anti-overstress function with respect to the lowercontact part 65 is exhibited.

FIGS. 10-13 show explanatory diagrams which illustrate a thirdembodiment of the female terminal of the present invention. FIG. 10 is aplan view, FIG. 11 is a sectional view along line 11--11 in FIG. 10,FIG. 12 is a sectional view along line 12-12 in FIG. 10, and FIG. 13 isa side view of the pressing part 85a in FIG. 10 from the directionindicated by arrow F.

FIGS. 10 through 13 show a female terminal 80 which is equipped with abottom plate 81, side plates 82a and 82b, upper contact parts 84a and84b, a lower contact part 85, a projection 86, a pressing part 85a, armparts 90a and 90b, arm part free ends 91a and 91b and the like.Furthermore, the broken line 89 indicates the insertion position of themating tab terminal.

In the female terminal 80 of the third embodiment of the presentinvention, the free ends 91a and 91b of the arm parts are bent back overthe upper contact parts 84a and 84b in positions located above the uppercontact parts 84a and 84b, so that the free ends 91a and 91b of the armparts perform an anti-overstress function with respect to the uppercontact parts 84a and 84b.

In the female terminal of the third embodiment, the pressing part 85aformed on the rear end portion of the lower contact part 85 is formed asfollows: after the rear end portion of the lower contact part 85 is bentin the direction indicated by arrow C with a bent portion 85c at therear end of the lower contact part 85 being used as a supporting point,the cross-sectional shape of the pressing part 85a is formed into an Sshape as shown in FIG. 11, and a second projection 85g is formed on thevertical portion of the pressing part 85a. This second projection 85g ispositioned directly above a projecting part 81h formed in thepunched-out portion of the rear end portion of the bottom plate 81.Accordingly, in cases where the tab terminal is inserted from anincorrect insertion direction, the second projection 85g contacts theprojecting part 81h, so that deformation of the lower contact part 85 isprevented. Thus, an anti-overstress function is obtained.

Furthermore, in the respective embodiments described above, examples ofterminals were described which were equipped with a pressing art formedby a process in which a portion of the lower contact part was cut andraised upward with the rear end portion of the lower contact part beingused as a supporting point. However, the present invention is notlimited to female terminals equipped with a pressing part of the type;it would also be possible to construct a female terminal equipped with apressing part formed by extending the lower contact part rearward as inthe conventional example described above. However, from the standpointof reducing the overall size of the female terminal, a terminal type inwhich the pressing part is formed by cutting and raising a portion ofthe lower contact part as in the respective working configurationsdescribed above is more desirable.

In the female terminal of the present invention, as was described above,arm parts which are separated from the side plates are bent back overupper contact parts which are formed by bending the free ends of theside plates inward so that these free ends face the bottom plate.Accordingly, deformation of the female terminal can be prevented even ifan abnormal force is applied to the upper contact parts when a tabterminal is inserted.

Furthermore, the pressing part disposed on the rear end portion of thelower contact part is formed by a process in which a portion of thelower contact part is cut and raised upward; accordingly, the overalllength of the female terminal is shortened, so that a compact femaleterminal can be obtained.

I claim:
 1. A female electrical terminal for electrical connection to amating tab terminal, comprisinga base plate having side plates extendingupwardly from the base plate; upper contact parts located at ends of theside plates extending over the base plate and substantially parallel tothe base plate; a lower contact part extending rearwardly from a forwardpart of the base plate and having a projection thereon for engaging ahole in the mating tab terminal; and arm parts extending upwardly fromthe base plate with free ends of the arm parts being disposed above theupper contact parts to provide overstress protection to the uppercontact parts.
 2. The female electrical terminal of claim 1, wherein thearm parts are part of the side plates.
 3. The female electrical terminalof claim 1, wherein protruding portions are provided at the free ends ofthe arm parts.
 4. The female electrical terminal of claim 1, wherein theupper contact parts have beads extending inwardly for electricalconnection with the mating tab terminal.
 5. The female electricalterminal of claim 1, wherein the lower contact part has a pressing partto release the projection from engagement with the hole of the matingtab terminal.
 6. The female electrical terminal of claim 5, wherein thelower contact part has a cantilever section on which the projection islocated and the pressing part extends upwardly from the cantileversection and is offset therefrom.